Lock for trailer hitch coupler nut

ABSTRACT

A lock for a trailer hitch coupler nut which can be used on couplers for trailer hitches to prevent the theft of a trailer when the trailer is connected to a towing vehicle, or is disconnected from the towing vehicle. The coupler nut has lockable elements that when locked prevent the nut from being turned to loosen the coupler.

United States Patent 1191 Vik LOCK FOR TRAILER HITCH COUPLER NUTInventor: Albam M. Vik, New Brighton,

Minn.

Assignee: Dempco, Inc., Minneapolis, Minn. Filed: Aug. 10, 1 972 Appl.No.: 279,648

Us. 01 70/231, 70/223, 280/507 1m. 01. B60d 1/12, Fl6b 41/00 Field ofSearch 70/221, 223, 231-; 280/507 References Cited UNITED STATES PATENTS.6 1930, Baird 70/231 Mar. 12, 1974 2,l 1 L51] 3/1938 Lowe et al 70/221Primary Examiner-Albert G. Craig, Jr. Attorney, Agent, or FirmRalph L.Rugger ABSTRACT A lock for a trailer hitch coupler nut which can be usedon couplers for trailer hitches to prevent the theft of a trailer whenthe trailer is connected to a towing vehicle, or is disconnected fromthe towing vehicle. The coupler nut has lockable elements that whenlocked prevent the nut from being turned to loosen the coupler.

9 Claims, 7 Drawing Figures l/l970 Thompson 280/507 1 LOCK FOR TRAILERHITCH COUPLER NUT BACKGROUND OF THE INVENTION 1. Field of the InventionThe present invention relates to lockable nuts used primarily fortrailer, hitch couplers so that the trailer cannot be easily attached toa towing vehicle.

2. Prior Art In the prior art there are various trailer couplers orvhitch locks. For example U.S. Pat. No. 3,226,133 shows a trailer hitchlocking device where a false ball is used for locking the coupler. Thisdevice is used when the trailer is uncoupled from the vehicle'towing thetrailer. Another type trailer hitch coupler lock is shown in U.S. Pat.No. 2,392,063 which will permit locking the trailer coupler when it isattached to the towing vehicle. Another type of lock for couplers isshown in U.S. Pat. No. 3,567,253. A special ball member that fits intothe trailer coupling housing when the trailer is not mounted on towingvehicles and .which can be used for locking or disabling a trailer hitchis shown in U.S. Pat. No. 3,492,023, and an additional safety lock fortrailer couplers is also shown in Pat. No. 3,514,980.

Key lock devices that operate to either engage .or disengage tworelatively movable members that can be rotated are common in locks forgas caps. An example of such a construction is shown in U.S. Pat. No.1,702,205. Theft preventing devices for locking spare tires in placewhich operate on a key lock principal are shown and used in U.S. Pat.Nos. 1,678,174; 1,516,453; and 1,635,228. In addition, U.S. Pat. No.3,540,245 shows a tamper proof lock nut for mounting wheels onto a car.

Reference is also made to the copending application of Vincent H.Murphy, Ser. No. 220,355, filed Jan. 24, 1972 entitled Lock For TrailerHitch Coupler, and assigned to the same assignee as this application.The Murphy application shows a locking nut of different lockconstruction.

SUMMARY OF THE INVENTION The present invention relates to a lockable nutthat may be used on a trailer hitch coupler to prevent the loosening ofthe nut when the coupler is attached to the automobile or when it isunhitched from an automobile or other towing vehicle. The devicecomprises a pair of members that are mounted relative to each other, onecomprising an outer housing and another comprising an inner member thathas a threaded center opening forming a nut that will thread onto thenormal coupler bolt of a ball type trailer hitch coupler (as shown).

away from the slots in the washer that normally keeps the nut fromrotating. The pins include drive portions that engage providedinterlocking pockets on the outer housing to effect a drive connectionbetween the outer housing and the inner nut portion. At this time then,when the outer housing is rotated it will drive the inner nut portion topermit the nut to be loosened.

The pins provide a positive lock for the nut in the locked position anda positive drive between the inner nut member member and the outerhousing in their unlocked position. Thus there is little chance thatexternal members could be used for jimmying the nut and making it comeloose when it is locked.

Therefore, the present invention comprises an easily lockable nut foruse on trailer couplers and similar items where a theft proof nut isdesired. The nuts are simple to manufacture and therefore low in cost,and

I can be used'with the trailer either coupled to a towing vehicle oruncoupled from the vehicle.

DESCRIPTION OF THE DRAWINGS FIG. 1 is-a side elevational view of atrailer hitch coupler having a coupler nut made according to the presentinvention installed thereon;

FIG. 2 is a sectional view taken as on line 2-2 of FIG. 1 with the nutin its locked position;

FIG. 3 is a sectional view taken as on line 33 of FIG. 2; I

FIG. 4 is a sectional view taken substantially on the same line as FIG.2 with the unit in its unlocked position; 4

FIG. 5 is a sectional view taken as on line 55 of FIG. 4;

FIG. 6 is a sectional view taken as on line 6--6 in 'FIG. 4; and v FIG.7 is a sectional view showing a typical lock washer used for locking theinner nut member with respect to the trailer hitch coupler.

DESCRIPTION or THE PREFERRED EMBODIMENT A'trailer hitch pole illustratedfragmentarily at 10 has a hitch coupler assembly 1 1 of usual design atthe outer end thereof designed to fit onto a coupler ball 12 that A keylock device is used for moving a cam member which actuates locking pinson the inner portion to a position wherein they will extend out throughthe bottom of the inner portion into openings in a washer that isprevented from rotating with respect to the trailer hitch coupler sothat the nut portion is prevented from rotating. The same pin membersare used for providing the disengageable drive between the inner nutmember and the outer housing of the nut.

In the locked position, when the pins extend into the openings in thewasher for locking purposes, the drive is disengaged, and the outerhousing of the nut will turn freely relative to the inner nut member. 7

When the key lock is used to move the cam to its un-' locked position,the pins will be permitted to retract will be mounted onto the trailerhitch of an automobile or other towing vehicle. The coupler 11 includesa ball socket portion 13, that will receive the ball 12, and a lockinglever or jaw 14 that is mounted on a suitable pivot pin 15 on thecoupler housing. The jaw 14 is moved about its pivot to lock against theunderside of ball 12 as shown in FIG. 1 through the use of a coupler Ibolt 16, that extends through the upper wall 17 of the coupler 11, andis threadably controlled by a coupler nut assembly illustrated generallyat 20. The nut assembly is made so that it can be made tamper proof inaccordance with the present invention. The nut assembly 20 permitslocking the coupler when the ball 12 is in place in the coupler socket13 or removed from the coupler.

The coupler nut assembly 20 includes an outer case or housing 21 thathas an upper hand grip-cam portion 22 and a lower portion 23. The outercase 21 has an interior chamber in which an inner nut member 24 isrotatably mounted, and the inner nut member 24 is held inside the lowerportion 23 by an annular shoulder or lip indicated generally at 25 atthe lower end of the outer housing. The nut portion 24 is retainedinside the interior cavity of the housing 21, and has a threadedinterior bore 26 that is threadably mounted on the bolt 16. The nutmember 24 is surrounded by the housing except for one exposed surface ofthe nut member at the bottom of the coupler nut assembly.

The upper portion 22 of the housing 21 mounts a key lock of usual designwhich has an outer housing 27 that is mounted so that it can slide in anout along the axis 28 of the nut housing but will not rotate about thisaxis when a key 29 is used in the unit. The key 29 operates an internaltumbler member 32 of the lock in the usual manner which has a lockingcam bar 31 drivably coupled thereto and held in place with a nut 33. Itshould be noted that when the outer lock housing 27 slides along itslongitudinal direction indicated by axis 28, the

interior tumbler assembly 32, which extends through the outer housing 27also moves in and out with respect surface portions 35 and two high camportions 36. The low cam surfaces are joined to one of the high camsurfaces, respectively, with ramp surfaces. In the low cam position asshown in FIG. 2, the locking cam bar 31 is underneath the low camsurface portions 35 and the lock assembly including the inner member 32,extends into the interior of the housing 21 the maximum amount. In ahigh cam position shown in FIG. 4, the locking bar is rotated 90 (thisis also shown in FIG. 6) and the outer key housing 27 can move outwardlyfrom the nut housing 21 as shown in FIG. 4 so that the cam bar 31 andthe inner member 32 move outwardly to the position shown in FIG. 4.

The inner nut member 24, which is rotatably mounted inside the nuthousing 21, includes means to selectively effect a drive connectionbetween the outer housing 21 andthe inner nut member 24. When the driveconnection is disengaged a positive lock to prevent rotation of the nutmember 24 with respect to the coupler bolt 16 is then provided. Asshown, the nut member 24 has a pair of locking pins 40 slidably mountedtherein for. movement along the axis of the locking pins generally inthe direction of axis 28. These locking pins 40 are spaced diametricallyon the nut, and have shanks extending through the inner nut member 24.The pin shanks are positioned to align with slot openings 41 in a washer42 that is mounted on the top wall 17."The washer 42 includes lockingtabs 43 that extend through slots 44 in the upper wall 17 (see FIG. 2and 7). These locking tabs 43 in the slots 44 prevent the washer 42 fromrotating with respect to the upper wall 17 of the coupler, and thus itcan be seen when the pins 40 are extending into the openings 41 the nutmember 24 cannot turn with respect to the bolt 16 more than the lengthof the slot openings. The pins form lock dogs for prevention of rotationof the inner nut member with respect to the bolt. It should be notedthat the bolt 16 also includes a tab 45 that will prevent the bolt 16from turning inside the jaw 14.

The pins 40 in addition to the elongated shank portion have driving headmembers 46 at the upper ends thereof. The heads 46 are mounted in largerrecesses 47 in the nut member 24 and will move axially. The heads 46 areenlarged annular flanges that are of suffi- I perhaps best seen in FIG.6, and includes. two low cam cient diameter so that they protrudeoutside of the normal pheriphery of the inner nut member 24 and theouter edge portions of these drive heads 46 indicated at 46A extend intoan annular groove 50 defined in the interior surface of the lowerportion 23 of the coupler nut housing 21. It should be noted that therecesses 47 provide open edges so that the pin heads 46 protrudeoutwardly beyond the edge of the nut housing. The pins 40 also haveactuator buttons 51 at the upper ends thereof. The actuator buttons 51extend upwardly from the heads 46.

The pins 40 are spring loaded in upwardly direction or in other wordstoward the upper portion 22 of the nut housing with springs 52positioned between the heads 46 and the surfaces at the bottom of therecesses 47 in the nut member and these springs spring load the pins 40upwardly, or in other words, in direction away from their lockingposition as shownin FIG. 2.

The buttons 52 are of sufficient height to extend upwardly to besubstantially on a level with the upper surface of the nut member 24when the pins are in position as shown in FIG. 2 with the heads46aligned with the annular recess 50. However, the pins 40 have to be heldin this position, and a large washer 54 is mounted inside the interiorcavity of the nut housing 21 and the washer '54 engages the actuatorbuttons 51 on both of the pins 40 and retains the pins in theirdepressed locking position shown in FIG. 2 when the cambar 31' is in itslock into the openings 41.

A spring 55 is also mounted in an interior recess in the center of thenut member 24 and this spring 55 bears against the bottom surface of thewasher 54 to urge it in upwardly direction as well.

The lower portion 23 of the coupler nut housing has an annular flangethat forms the upper wall above the groove 50 (see FIG. 3). This flange60 has four receptacles 61 defined therein and which extend outwardlyfrom the inner edgeof the flange so thatthe outer edges of thereceptacles 61 are substantially in line with the outer edge of thegroove 50. As shown in FIG. 3, the heads 46 of the pins extend underthis flange 60, when the pins are in locked position and the outerhousing 21 can turn with respect to the inner nut 24 freely becausethere is no driving connection between the nut 24 and the outer housing21. The lock member 27 will also rotate of course with the outer nuthousing 21 and the end of inner tumbler member 32 will rotate on theupper surface of the washer 54 without any difficulty. The washer 54 andinner nut will not turn.

However, asshown in FIG. 4 when the key 29 is turned to release theinner tumbler member 32 the cam lock bar 31 will be rotated to the highcam position defined by surfaces 36. The spring 55, and also the springs52 will urge the washer 54 and the pins 40, re-' spectively, upwardlywith respect to the nut member 24 and this spring loading will urge thepin heads 46 up against the underside of flange 60. When the outerhousing then is rotated to position wherein the pin heads 46 and two ofthe recesses 61 align, the pin heads will snap upwardly into the alignedrecesses 61 and the outer edge portions 46A of the pin heads will gointo the recesses 61 as shown in FIG. 4. The outer housing 21 will thenbe drivably connected to the inner nut member. In other words thesurfaces definingthe receptacles 61 will engage the edges of the pinheads 46 in portions 46A and there will be a driving connection betweenthe outer housing assembly 21 and the inner nut member 24 so that theinner nut member can be rotated. It should also be noted that when theunit is in its position as shown in FIG. 4 the pins 40 are withdrawnfrom the openings 41 in the retainer washer 42 and the entire nutassembly then will be driven as a unit and operate as a nut by'turningthe outer housing to thread the nut member 24 with respect to the bolt16. This permits loosening or tightening the nut on the bolt. The outerlock housing 27 moves upwardly as shown in FIG. 4. away from the uppersurface of the upper member 22 of the housing in this unlocked position.

When the device is again to be locked, the key 29 and the housing 27will be pushed down (the ends of pins 40 will have to be aligned withslots 41' before the lock can be depressed), and the key 29 rotated tothe locked position with the cam bar 31 under the low cam surfaces 35 onthe inner end surface of the receptacle in the outer nut housing 21. Thepins 40 will be moved to their position as shown in FlG. 2 so that theouter portions 46A of the pin heads 46 move down into alignment with thegroove 50. The edge portions 46A no longerengage the receptacles 61 andthe outer nut housing 21 can be freely rotated with respect to the innernut member 24. It should be noted that the unit cannot be locked or inother words the lock bar 31 cannot be moved to its low cam positionuntil the pins 40 enter the slots 41 of the washer 42. The use of slotsmakes alignment relatively easy. Once the pins extend into the slots 41it is insured that the inner nut member 24 is held positively fromrotation. The washer 42 is held from rotation by lugs 43 so that the nut24 cannot be unfastened from bolt 16. The lower portion 23 of the outerhousing 21 has an annular flange 23A that surrounds the edge of washer42. This prevents the use of bars or picks to loosen the washer.

If desired, a small collar or tubular lock member 67 can be mounted overthe bolt 16 below wall 17, and then the coupler can be locked evenwithout the ball 12 in place. The nut can be tightened until the bolt 16draws up against the lock sleeve 67 so that the sleeve 67 is against theundersurface of the top wall 17 so that the unit can be tightly held.When the jaw is in its raised position a ball cannot be inserted. Withthe nut locked as explained the trailer cannot be attached to a vehicleand stolen. A spring also may be used on the bolt 16 below the couplerwall 17 to cause the jaw 14 to open as the nut is unthreaded.

The nut unit is quite simple to make, and it should be noted that thespring 55 is of sufficiently large inner diameter to clear the bolt 16.The springs acting on the washer 54 and the pins 40 urge the lockhousing 27 and pins 40 to unlocked position at all times so thatwhenever the key is operated to turn the cam lock bar 31 to its unlockedposition the key housing 27 will slide upwardly to its position as shownin FIG. 4. The unit then will be unlocked, or in other words there willbe a driving connection between the outer nut housing and the nutmember24 and as soon as the edge portion 46A of heads 46 snap intoreceptacles 61 so that the nut can be threaded onto or removed from thebolt 16. Again it is to be understood that the outer lock housing 27does not rotate with respect to the outer nut housing, but merely slidesin axial direction so that the rotation of the key 29 will cause theinner member 23 of the lock to rotate the cam lock bar 31 between itshigh cam and low cam positions. v

The inner nut member or housing is assembled inside the outer housing 21before the two portions 22 and 23 are welded together. The inner nutmember or housing is assembled in place and rotatably held while beingcompletely shielded.

What is claimed is:

1.- An antitheft nut assembly for attaching to a bolt member includingan outer housing, an inner housing rotatably mounted inside said outerhousing, means on said inner housing defining an opening threadable ontosaid bolt, lock dog means carried by said inner housing and movable froma locking position wherein said lock dog means protrudes outside saidinner housing to an unlocking position, means engageable by said lockdog means to prevent rotating said lock dog means and inner housing withrespect to said bolt a substantial amount with the lock dog means insaid locking position, and complemental drive means on said inner andouter housings positioned to be drivably engaged with respect. to eachother when lock dog means is moved to its unlocking position anddisengaged with the lock dog means protruding outside said innerhousing.

2. The combination as specified in claim 1 wherein said lock dog meanscomprises pin means slidable mounted in said second member along an axissubstantially parallel to the axis of the bolt, said pin meansprotruding out beyond the bottom surface of said inner housing, aretainer means mounted below said second member, and means to hold saidwasher means from rotation with respect to saidbolt, said retainer meanshaving a plurality of openings therein to receive said pins when saidpins are in said locking position.

3. The combination as specified in claim 2 and cam operated lock meansmounted on said outer housing and movable to and from positions whereinsaid cam lock means moves said pins between said locking and unlockingpositions.

4. The combination as specified in claim 3 and spring means urging saidpins to their unlocking position.

5. The combination as specified in claim 3 wherein said pins includehead portions projecting outwardly from the main part of the pins, andreceptacle means defined in portions of said outer housing, saidportions of said pins engaging said receptacle means to effect saiddriving connection when said pins are in said unlocking position.

6. A theft preventive nut assembly for use on a trailer coupler having abolt used for attaching the coupler to a towing vehicle including anouter housing, an inner housing retained within said outer housing androtatably mounted with respect thereto, said inner housing inner andouter housings are not drivably engaged to an unlocked position toeffect a rotational drive connection between said inner and outerhousings, and lock means to substantially simultaneously move one ofsaid receive the end portion of said pin when the inner housing isthreaded onto said bolt.

8. The combination as specified in claim 7 wherein said third and fourthmeans comprise interlocking projection and receptacle means, one of saidthird and fourth means being defined on said pin and the other of saidthird and fourth means being defined on said outer housing.

9. The combination as specified in claim 8 wherein said pin is slidablymounted in said inner housing and spring means urging said pin towardsaid unlocked position. v

23x 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent NDated March Inventor(s) Albam MD Vik It is certified that error appearsin the above-identified patent and that said Letters Patent are herebycorrected as shown below:

r Column 3, line 8 "an" should be--and='-- Column 6, line 30 (Claim 2,line 2) "slidable" should be--slidably--; Column 6, line 31, (Claim 2,line 3) take out "second member" and insert "inner housing.--; Column 6,lines 34 and 35, (Claim 2, lines 6 and 7) take out "second member" andinsert--inner housing--; Column 6, line 51, (Claim 5, line 6) take out"driving connection" and insert--drivable engagement--; Column 6, line63, (Claim 6, line 11) "lock" should be--locked--; Column 6, line 67,(Claim 6, line 15) take out "an unlocked" and insert- -a locked--.

Signed and sealed this 17th day of September" 1974.

(SEAL) Attest:

McCOY M. GIBSON JR'. I c. MARSHALL DANN Attesting Officer Commissionerof Patents

1. An antitheft nut assembly for attaching to a bolt member including anouter housing, an inner housing rotatably mounted inside said outerhousing, means on said inner housing defining an opening threadable ontosaid bolt, lock dog means carried by said inner housing and movable froma locking position wherein said lock dog means protrudes outside saidinner housing to an unlocking position, means engageable by said lockdog means to prevent rotating said lock dog means and inner housing withrespect to said bolt a substantial amount with the lock dog means insaid locking position, and complemental drive means on said inner andouter housings positioned to be drivably engaged with respect to eachother when lock dog means is moved to its unlocking position anddisengaged with the lock dog means protruding outside said innerhousing.
 2. The combination as specified in claim 1 wherein said lockdog means comprises pin means slidable mounted in said second memberalong an axis substantially parallel to the axis of the bolt, said pinmeans protruding out beyond the bottom surface of said inner housing, aretainer means mounted below said second member, and means to hold saidwasher means from rotation with respect to said bolt, said retainermeans having a plurality of openings therein to receive said pins whensaid pins are in said locking position.
 3. The combination as specifiedin claim 2 and cam operated lock meAns mounted on said outer housing andmovable to and from positions wherein said cam lock means moves saidpins between said locking and unlocking positions.
 4. The combination asspecified in claim 3 and spring means urging said pins to theirunlocking position.
 5. The combination as specified in claim 3 whereinsaid pins include head portions projecting outwardly from the main partof the pins, and receptacle means defined in portions of said outerhousing, said portions of said pins engaging said receptacle means toeffect said driving connection when said pins are in said unlockingposition.
 6. A theft preventive nut assembly for use on a trailercoupler having a bolt used for attaching the coupler to a towing vehicleincluding an outer housing, an inner housing retained within said outerhousing and rotatably mounted with respect thereto, said inner housingbeing exposed only on one surface and having an opening defined thereinthreaded to threadably receive said bolt, first and second means mountedon said inner housing and said coupler movable between a locked positionand an unlocked position, said first and second means engaging in lockposition to prevent substantial rotation of said inner housing withrespect to said bolt, third and fourth means on said inner housing andsaid outer housing, said third and fourth means being relatively movablefrom an unlocked position where the inner and outer housings are notdrivably engaged to an unlocked position to effect a rotational driveconnection between said inner and outer housings, and lock means tosubstantially simultaneously move one of said first and second means andone of said third and fourth means to their respective locked positions.7. The combination as specified in claim 6 wherein said first meanscomprises at least one pin slidably mounted in said inner housing, anend portion of said pin protruding from said inner housing in the lockedposition, and said second means comprising a receptacle defined in amember that does not rotate with respect to said bolt, said receptaclebeing positioned to receive the end portion of said pin when the innerhousing is threaded onto said bolt.
 8. The combination as specified inclaim 7 wherein said third and fourth means comprise interlockingprojection and receptacle means, one of said third and fourth meansbeing defined on said pin and the other of said third and fourth meansbeing defined on said outer housing.
 9. The combination as specified inclaim 8 wherein said pin is slidably mounted in said inner housing andspring means urging said pin toward said unlocked position.